Footwear traction assist

ABSTRACT

Winter boots and shoes can be equipped with a removable traction attachment that facilitates easy non-slip motion on ice, snow, dirt, gravel, etc. The traction attachment can include an elastomeric panel fitting the sole of the boot or shoe, an integral front strap system fitting over the toe of the boot, and an integral rear strap system fitting snugly on the heel of the boot. The panel and strap systems have controlled elasticity, so that a given size attachment can fit a range of different size boots or shoes. Replaceable metal cleats are carried on downwardly protruding sections of the elastomeric panel, to provide traction assistance.

FIELD OF THE INVENTION

[0001] This invention relates to a traction attachment for footwear, especially a traction attachment for use under wintry or arctic conditions on icy or snow covered terrain.

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] The invention concerns a traction device that can be readily installed on a person's boot or shoe to provide improved traction on snowy or icy terrain. The device can be likened to snow tires for the feet. An important object of the invention is to provide a traction attachment that is rugged and stable on the person's boot, but is at the same time very light in weight. Typically, the attachment weighs only about six ounces, such that it offers no measurable hindrance to each foot movement.

[0003] A typical prior art traction attachment is shown in U.S. Pat. No. 5,813,143, issued on Sep. 29, 1998 in the name of Michael Bell. That patent shows an integral one piece unit molded out of resilient material, e.g. rubber or polyvinyl chloride, and adapted to fit onto a person's footwear (boot or shoe) to provide improved traction for the person.

[0004] The molded unit includes a sole, toe encirclement at the front end of the sole, and a heel encirclement at the rear end of the sole. The heel encirclement includes side straps that are stretchable, so that the molded unit can fit more than one size boot or shoe. The shank area (or arch area) of the sole has a large rectangular opening, apparently for reducing the resistance of the molded unit to longitudinal stretching (while the unit is being placed on the footwear). Several spikes, or cleats, are secured to the bottom surface of the molded sole, to provide an improved traction on snow or ice.

[0005] The present invention relates to a footwear traction attachment that includes a flexible molded panel adapted to fit against the footwear sole, an integral front strap means for fitting around the toe of the footwear, and an integral rear strap means for fitting around the heel of the footwear. The flexible panel includes a shank area that is of reduced thickness and width (compared to the heel and toe areas), such that the shank area is stretchable longitudinally to vary the spacing between the toe and heel areas of the panel. The panel construction enables the traction attachment to be readily stretched, so as to fit a range of different footwear sizes. Typically, four half sizes can be accommodated with a single traction attachment size.

[0006] The front strap means and the rear strap means are formed of a stretchable (elastomeric) material, so as to be stretchable independently of the aforementioned panel. Therefore, the strap means can fit snugly on differently shaped footwear toes or heels, without regard to stretch or non-stretch of the flexible panel.

[0007] The traction attachment includes multiple metal cleats replaceably secured to the flexible panel in the frontal area and heel area of the panel (but not in the shank area). Each cleat has a threaded post section that threads into a threaded socket embedded in a raised (or protruding) island integrally formed on the panel.

[0008] Each metal cleat can include an annular hollow cup-shaped traction configuration having a sharpened annular edge designed to bite deeply into ice or snow. Each metal cleat can be replaced should it become worn or damaged.

[0009] In preferred practice of the invention, the flexible panel (covering the sole of the footwear) is formed of two separate layers of elastomeric material, i.e. an upper layer is preferably a low durometer material, e.g. an elatomer having a durometer of approximately thirty-seven. The lower layer is a high durometer material, e.g. an elastomer having a durometer of about 70. The upper layer material is selected primarily for its ability to stretch (for achieving a snug fit on a range of different footwear sizes and shapes). The lower layer material is selected primarily for durability and abrasion resistance.

[0010] Upper and lower panel layers are bonded together along their facing surfaces. Additionally, mechanical interlocking connections are employed between the two elastomeric layers, to provide a laminated panel resistant to delamination forces. In one preferred arrangement, the lower panel is molded to have multiple protuberances designed to fit into mating openings in the upper layer, whereby the two layers are mechanically locked together so as to resist shear forces that might tend to produce delamination of the two layers.

[0011] The protuberances on the lower layer are vertically aligned with the raised islands that anchor the aforementioned cleats. Therefore, the cleat anchorages are reinforced against terrain forces that might tend to disturb or tear the cleats from the laminated panel. The cleats have improved resistance against wobbling or shifting relative to the panel while the person's foot is exerting a traction force on ice or frozen terrain.

[0012] The number of cleats employed on the traction attachment can vary. In a preferred embodiment of the invention nine cleats are employed. Five cleats are mounted on the frontal area of the flexible panel, and four cleats are mounted on the heel area of the panel. In order to minimize build up of ice or snow between the traction attachment panel and the sole of the footwear, the panel is molded to include drainage notches or grooves at spaced points along the panel edge. As the person's foot applies downward pressure on the traction attachment panel, any snow or ice accumulations in the interface between shoe sole and attachment tend to be squeezed into the drainage grooves and out onto the terrain. The drainage grooves allow any ice, snow or water to drain out of the interface between the footwear sole and traction attachment, thus reducing the overall loading on the person's foot.

[0013] As stated earlier, an important object of the invention is to provide a traction attachment that is rugged and stable on the person's foot, but is at the same time very light in weight. In one particular embodiment of the invention, the traction attachment weighs about six ounces. The low weight is attributable, at least in part, to the fact that the traction panel is a laminated two layer construction in which the upper layer is a low durometer elastomer that is stretchable to conform to the footwear, while the lower layer is a high durometer elastomer that is tough and resistant to abrasion forces. By using two different elastomers it is possible to optimize the wall thickness of each layer for its intended function, while at the same time holding the overall weight within reasonable limits.

[0014] Specific features and advantages of the invention will be apparent from the attached drawings and description of an illustrative embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a side elevational view of a traction attachment constructed according to the invention. The footwear, on which the attachment is installed, is shown in dashed lines.

[0016]FIG. 2 is a top plan view of the traction attachment depicted in FIG. 1.

[0017]FIG. 3 is a sectional view taken on line 3-3 in FIG. 2.

[0018]FIG. 4 is a bottom plan view of FIG. 3 construction.

[0019]FIG. 5 is an enlarged cross sectional view taken on line 5-5 in FIG. 4.

[0020]FIG. 6 is a fragmentary view taken in the direction of arrow 6 in FIG. 5.

[0021]FIG. 7 is a bottom plan view of an elastomeric panel component employed in

[0022]FIG. 8 is a top plan view of two other panel components used in combination with the FIG. 6 component, to produce a multi-layer panel, according to the invention.

[0023]FIG. 9 is a view taken in the same direction as FIG. 3, but showing another form that the invention can take. FIG. 3 represents a preferred embodiment of the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0024] Referring to FIGS. 1 and 2, there is shown a traction attachment 10 constructed according to the invention. The attachment is shown in an installed position on a person's shoe or boot 12, shown in dashed lines. The term “footwear” will be used herein as a generic description for a person's boot or shoe of a type that is worn by a person when walking, climbing or hiking on snow or icy terrain. The traction attachment 10 is designed to provide increased traction on snow or icy surfaces, as well as dirt or gravel.

[0025] The traction attachment includes a flexible panel 14 adapted to fit flatwise against the sole of footwear 12, a front strap means 16 carried by the panel for fitting around the toe of the footwear, and a rear strap means 18 carried by the panel for fitting around the heel of the footware. Each strap means 16 or 18 is formed of a low durometer elastomer, so that the strap means can stretch to a limited extent for snugly fitting differently sized or differently shaped toes and heels of footwear.

[0026] Flexible panel 14 carries nine downwardly projecting steel cleats 44 that provide traction in ice, snow, dirt, gravel, etc. FIG. 4 is a bottom view of panel 14, showing the cleat 44 pattern. Five cleats are mounted on the frontal section 31 of the panel. Four cleats 44 are mounted on heel section 32 of the panel. Shank area 33 of the panel is devoid of cleats.

[0027]FIG. 5 shows a mechanism for anchoring each metal cleat 44 to panel 14. Each cleat includes a threaded post that threads into a metal socket 42, embedded or encapsulated, within a thickened section of panel 14, whereby the socket is precluded from tearing away from the panel. Each metal cleat can be replaced should it become worn or damaged.

[0028] As indicated earlier, the flexible panel 14 is secured to the footwear (boot or shoe) 12 by a front strap means 16 and a rear strap means 18.

[0029] Strap means 16 is a low durometer elastomer that includes a front central strap element 19 located on the longitudinal axis 20 of the footware attachment, and two side strap elements 21 and 22 connected to each side edge of panel 14. The strap elements merge together to form a central bridge 24 that is adapted to overlie the upper surface of the toe on footware 12. The strap elements are elastic so as to fit snugly on a range of different footwear toe sizes and styles.

[0030] Strap means 18 includes a cross piece 26 adapted to fit against a rear central surface of the footware heel, and two strap elements 27 and 28 extending downwardly and forwardly from each end of the cross piece to connect with edge areas of panel 14. The cross piece and associated strap elements 27 and 28 are formed of a low durometer elastomer, such that the cross piece can stretch to a limited extent for conforming to differently dimensioned footwear heel surfaces. Plural ridges 29 (FIG. 3) are formed on the front surface of cross piece 26, to ensure an improved grip of the cross piece on the footwear heel surface.

[0031] The cross sectional dimensions of the cross piece and strap elements are selected, in conjunction with the durometer of the elastomer, to achieve a desired elasticity of the front strap means 16 and rear strap means 18, whereby the strap mechanisms are enabled to snugly fit a range of different footwear toe and heel styles and sizes. The durometer of the elastomer used for strap means 16 and 18 is preferably about thirty-seven.

[0032] Panel 14, is a dual density multi-layer laminated construction formed out of two different elastomers. FIGS. 7 and 8 show the panel components in plan view. The upper layer (or lamination) 30 is show in FIG. 7; it includes a frontal section 31, heel section 32 and shank 33 connecting the frontal and heel sections. The upper layer is formed of a relatively soft elastomer having a durometer of about thirty-seven. The vertical thickness of layer 30 is preferably about 0.16 inch. Nine toothed openings 34 are formed in layer 30 to mate with similarly shaped protuberances 36 formed on two lower layers 38 and 40 (when the lower layers are bonded to the upper layer).

[0033] Lower layer 38 has a shape that conforms to the shape of frontal section 31 of the upper layer, so that when layer 38 is bonded to the undersurface of layer section 31, protuberances 36 fit snugly into the mating openings 34 to form a mechanical interlock between layers 30 and 38.

[0034] Lower layer 40 has a shape that conforms to the shape of heel section 32 of layer 30. Four protuberances 36 on the upper surface of lower layer 40 fit into the aligned toothed openings 34 on heel section 32 to form a mechanical interlock between layers 30 and 40 (when layer 40 is bonded to layer 30).

[0035] Protuberances 36 are vertically aligned with certain internally threaded metal sockets 42 that serve as anchorages for hardened steel cleats 44 (FIG. 5), such that protuberances 36 transfer a fraction of the traction force from the cleats to upper layer 30 of panel 14, while at the same time reinforcing the elastomeric material in contact with sockets 42. Protuberances 36 absorb shear loadings on the interfaces between layers 38 and 40, and upper layer 30, thereby protecting the laminated panel from delamination forces that occur when the person exerts a pushing or pulling force on icy terrain.

[0036] Lower layers 38 and 40 are formed of an elastomer having a relatively high durometer, e.g. an elastomer having a durometer of about seventy. The layer material is selected primarily for toughness and abrasion resistance. The aim is to preclude the metal cleats 44 from exerting oblique forces on the elastomeric material in contact with sockets 42, which could eventually tear the sockets out of the elastomer. The nominal thickness of each layer 38 or 40 is only about 0.16 inch. However, protuberances 36 effectively increase the layer thickness in those areas that are used to mount the cleat sockets.

[0037] By comparing FIGS. 7 and 8, it will be seen that the laminated panel 14 is relatively thick in the frontal section of the panel and in the heel section of the panel. The shank area 33 of the panel is formed solely by upper layer 30, such that the shank area is relatively thin in the vertical (thickness ) direction.

[0038] Shank area 33 has a cross sectional dimension that enables the shank area of the laminated panel to stretch longitudinally, while the frontal section and heel section of the panel are substantially non-stretchable. In this regard, the high durometer layers 38 and 40 tend to add stretch resistance to the panel, while the low durometer shank area 33 has the desired elasticity needed for localized longitudinal stretching of the panel, e.g. for stretching the panel to fit a range of different footwear sizes. Panel 14, is a dual density panel, that is adapted to have a tension fit binding on a range of different size footwear.

[0039] In FIG. 5 the longitudinal axis of panel 14 is referenced by numeral 20. Shank area 33 of the panel has a width dimension 52 (transverse to axis 20) that is substantially less than the corresponding width dimension for the frontal section or heel section of the panel. Typically, width dimension 52 will be about thirty-five millimeters. The cross sectional dimension of the shank area 33 (thickness and width) is selected, along with the durometer of panel lamination (layer) 30, so that the panel stretch action is confined to shank area 33.

[0040] As viewed in FIG. 5, edges 53 of shank area 33 are concave so that the shank width dimension is increased where the shank area connects with the transverse edges 54 and 55 of the panel frontal section and heel section. The increased width dimension strengthens those parts of the shank area most likely to tear or rupture when the panel is subjected to a longitudinal stretching force, i.e. the anchored ends of the shank that cannot relieve the stress in the form of strain.

[0041] Although not readily apparent from the drawing the front strap means 16 and rear strap means 18 are integral with upper layer 30 of panel 14, preferably by molding the panel layer 30 and strap means together in a single step molding operation. The panel layer 30 and both strap means are formed of the same low durometer elastomer so as to have a desired elasticity.

[0042] In adapting a given size traction attachment to fit a range of different footwear sizes and shapes, there are two independent stretching actions that can take place. First, panel 14 can be stretched longitudinally in shank area 33 to vary the spacing between the front strap means 16 and rear strap means 18. Second, the front strap means 16 can be independently stretched to have a snug fit on various different footwear toe sizes and styles. Similarly, the rear strap means 18 can be independently stretched to fit a range of footwear heel configurations. In this regard, cross piece 26 curls around a substantial length of the heel surface so as to be capable of substantial changes in cross piece length.

[0043] Referring to FIGS. 4 and 5, it will be seen that the steel cleats 44 are located at spaced points along the peripheral edge of panel 14, giving the traction attachment a wide stance tractive action for improved footware stability. The central area of panel 14 proximate to the longitudinal centerline 20 is occupied by two sets of chevron type treads 57 and 58 extending downwardly from frontal layer 38 and heel layer 40. Chevrons 57 have rearwardly facing ve rtical surfaces that stabilize the panel against slippage in the rearward direction, whereas chevrons 58 have forwardly facing vertical surfaces that stabilize the panel against slippage in the forward direction. The chevrons augment the tractive action of cleats 44.

[0044] As stated earlier, each metal cleat 44 is threadably mounted in a metal socket 42 encapsulated within one of the lower layers 38 or 40 of the laminated elastomeric panel. Each metal cleat includes an annular cup-like protrusion that has an annular sharpened edge 60 designed to bite into icy terrain so as to achieve a tractive action. The annular wall of the hollow cup-like protrusion has a screw driver slot 62 therein that facilitates installation or removal of the cleat from the associated socket 42. All of the cleats are similarly constructed.

[0045] Each metal socket 42 is encapsulated within an island 64 protruding from the laminated panel 14, to provide lateral support for the socket. As shown in FIG. 5, the side surface of the protruding island is stepped to provide some traction in soft terrain. The islands are molded integrally with elastomeric laminations (layers) 38 and 40.

[0046] As previously noted, metal sockets 42 are vertically aligned with protuberances 36 on elastomeric layers 38 and 40. Therefore, the elastomeric material encircling each socket 42 is reinforced by the associated protuberance 36. Shear loadings on the metal cleats 44 tend to be resisted by the associated protuberances 36 that are mechanically locked to the upper lamination 30 of the cleat-support panel. Protuberances 36 tend to resist panel delamination forces.

[0047] The laminated panel 14 is provided with plural drainage, and is provided with plural drainage grooves 66 interspersed with metal cleats 44 at spaced points along the peripheral edge of the panel. As shown in FIG. 4, there are four V-shaped drainage grooves 66 in the frontal portion of the laminated panel, and two drainage grooves 66 in the heel portion of the panel. Each drainage groove is located between two cleats, so as to be capable of shedding snow or water that might accumulate in the spaces between cleats. The drainage grooves extend through the entire panel thickness, so that water or ice accumulations in the crack interface between the footwear sole and upper surface of panel 14, can migrate easily into the drainage grooves.

[0048] The apex of each V-shaped drainage groove 66 forms a potential weak point that could lead to tearing or rupture of the elastomeric materials. To strengthen the panel against such rupture, each lower layer 38 or 40 has molded reinforcement ribs 68 that provide local reinforcements at the apex of each V-shaped drainage groove, as well as longitudinal rigidification of layers 38 and 40.

[0049] The traction attachment is designed to achieve a combination of useful properties, including localized elasticites enabling a given size attachment to fit a range of different footwear sizes, a good stable support for each metal cleat, drainage for ice of snow accumulations, and a relatively low overall weight.

[0050] As shown in FIG. 4, the longitudinal centerline 20 is a straight line, such that the traction attachment is capable of fitting on either a left boot or a right boot. In actual practice the attachment is made in two versions, i.e. for a left shoe or a right shoe; the longitudinal centerline is slightly curved.

[0051]FIG. 3 shows a preferred embodiment of the invention. FIG. 9 shows an alternate construction that can be employed. In the FIG. 9 version panel, 14 is a single molded elastomer having a durometer of approximately fifty. The FIG. 9 panel represents a compromise between elasticity and durability.

[0052] The drawings show specific forms that the invention can take. However, it will be appreciated that the invention can be practiced in various forms and configurations. 

What is claimed
 1. A traction attachment for footwear, wherein the footwear comprises a sole that includes a toe section, a heel section, and an arch section connecting said toe and heel sections; said traction attachment comprising: a flexible panel adapted to fit against the footwear sole; a front strap means carried by said panel for fitting around a toe of the footwear; and a rear strap means carried by said panel for fitting around a heel of the footwear; said flexible panel comprising a frontal area, heel area, and shank area connecting the frontal area and heel area; said shank area having a lesser vertical thickness than the frontal area or the heel area, so that the shank area is stretchable while the frontal and heel areas are substantially non-stretchable heel areas are substantially non-stretchable, whereby the spacing between the front strap means and the rear strap means can be varied to accommodate a range of different footwear sizes.
 2. The traction attachment of claim 1, wherein said panel has a longitudinal axis; the frontal area, heel area and shank area of said panel having differing width dimensions measured transverse to the panel longitudinal axis; the width dimension of said shank area being substantially less than the width dimension of said heel area, whereby said shank area is stretchable along the panel longitudinal axis.
 3. The traction attachment of claim 2, wherein the width dimension of said shank area is approximately thirty-five millimeters.
 4. The traction attachment of claim 3, wherein said shank area has a thickness of approximately 0.16 inch.
 5. The traction attachment of claim 2, wherein said shank area has concave side edges that merge smoothly with transverse edges of the frontal area and heel area.
 6. The traction attachment of claim 1, wherein said panel is a dual density multi-layer assembly that includes a single upper lamination, and two separate lower laminations; one of the lower laminations being secured to the frontal area of the upper lamination, the other lower lamination being secured to the heel area of the upper lamination: said upper lamination forming the shank area of the flexible panel.
 7. The traction attacahment of claim 6, wherein said upper lamination is formed of an elastomeric material having a relatively low durometer, and each said lower lamination is formed of an elastomeric material having a relatively high durometer.
 8. The traction attachment of claim 7, wherein the durometer of said upper lamination is approximately thirty-seven, and the durometer of each said lower lamination is approximately seventy.
 9. The traction attachment of claim 1, and further comprising plural replaceable cleats extending downwardly from said flexible panel at spaced points along the panel peripheral edge; said plural cleats including five cleats located on the frontal area of the panel, and four cleats located on the heel area of the panel; the shank area of said panel being devoid of cleats.
 10. The traction attachment of claim 9, and further comprising plural drainage grooves formed in the peripheral edge of said flexible panel; said drainage grooves being located between the cleats in the frontal area and heel area of the panel.
 11. The traction attachment of claim 10, wherein each drainage groove has a configuration in the plan view.
 12. A traction attachment for footwear, wherein the footwear comprises a sole that includes a toe section, a heel section, and an arch section connecting said toe and heel sections; said traction attachment comprising: a flexible panel adapted to have a tension fit against the footwear sole, a front strap means carried by said panel for fitting around a toe of the footwear, and a rear strap means carried by said panel for fitting around a heel of the footwear; said flexible panel comprising a frontal area, heel area, and shank area connecting the frontal area and heel area; said shank area having a lesser vertical thickness than the frontal area or the heel area, so that the shank area is stretchable while the frontal and heel areas are substantially non-stretchable, whereby the spacing between the front strap means and the rear strap means can be varied to accommodate a range of different footwear sizes; said panel being a multi-layer assembly that includes a single upper lamination, and two separate lower laminations; one of the lower laminations being secured to the frontal area of the upper lamination, the other lower lamination being secured to the heel area of the upper lamination; said upper lamination forming the shank area of the flexible panel; said upper lamination being formed of an elastomeric material having a relatively low durometer, and each said lower lamination being formed of an elastomeric material having a relatively high durometer; each lower lamination having plural protruding islands located at spaced points along the panel peripheral edge; a threaded socket embedded in each said island; and an externally threaded cleat, replaceably secured within each said socket.
 13. The traction attachment of claim 12, wherein said upper lamination has plural openings aligned with the aforementioned threaded sockets; said lower laminations having protuberances extending into said openings, whereby the elastomeric material surrounding each socket is reinforced against tearing or rupture.
 14. The traction attachment of claim 13, and further comprising plural drainage grooves formed in the peripheral edge of said flexible panel.
 15. The traction attachment of claim 14, wherein each drainage groove has a V configuration in the plan view.
 16. The traction attachment of claim 12, wherein said rear strap means is integral with the heel area of said flexible panel, said front strap means and said rear strap means being individually stretchable; the shank area of said flexible panel being stretchable independently of the front strap means or the rear strap means.
 17. A traction attachment for footwear, wherein the footwear comprises a sole that includes a toe section, a heel section, and an arch section connecting said toe and heel sections; said traction attachment comprising: a flexible elastomeric panel adapted to fit against the footwear sole, a front strap means carried by said panel for fitting around a toe of the footwear, and a rear strap means carried by said panel for fitting around a heel of the footwear; said flexible panel comprising a frontal area, heel area, and shank area connecting the frontal area and heel area; said flexible panel having plural downwardly protruding islands located in the frontal area and heel area of the panel; a threaded socket embedded in each said island; an externally threaded cleat having a replaceable screw fit in each socket; and plural drainage grooves formed in the peripheral edges of said frontal area and said heel area.
 18. The traction attachment of claim 17, wherein said drainage grooves are interspersed with the cleats so that each drainage groove is located between two cleats.
 19. The traction attachment of claim 18, wherein each drainage groove has a V configuration in the plan view.
 20. The traction attachment of claim 17, wherein each said cleat has an annular sharpened edge 60, designed to bite into icy terrain. 